TL;DR

Neocons is a feature rich idiomatic Clojure client for the Neo4J REST API.

2.0.0-beta2 is a development milestone that targets Neo4J 2.0 and drops Clojure 1.3 support but otherwise is backwards compatible.

With this release, we begin introducing new features to Neocons that are specific to Neo4J 2.0.

Changes between Neocons 1.1.0 and 2.0.0-beta2

Clojure 1.3 Support Dropped

Neocons no longer supports Clojure 1.3.

Transaction Support (Neo4J Server 2.0)

Neocons 2.0 gains support for transactions.

Higher Level API

A group of Cypher statements can be executed in a transaction that will be committed automatically upon success. Any error during the execution will trigger a rollback.

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(require '[clojurewerkz.neocons.rest.transaction :as tx])

(tx/in-transaction
  (tx/statement "CREATE (n {props}) RETURN n" {:props {:name "Node 1"}})
  (tx/statement "CREATE (n {props}) RETURN n" {:props {:name "Node 2"}}))

Lower Level API

Transactions are instantiated from a group of Cypher statements that are passed as maps to clojurewerkz.neocons.rest.transaction/begin:

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(let [t (tx/begin-tx [{:statement "CREATE (n {props}) RETURN n" {:props {:name "My node"}}}])]
  (tx/commit t))

(let [t (tx/begin-tx)]
  (tx/rollback t))

clojurewerkz.neocons.rest.transaction/commit and clojurewerkz.neocons.rest.transaction/rollback commit and roll a transaction back, respectively.

Macro for working with a transaction

If you want a more fine grained control of working in a transaction without manually committing or checking for exceptions, you can use the clojurewerkz.neocons.rest.transaction/with-transaction macro.

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(require '[clojurewerkz.neocons.rest.transaction :as tx])

(let [transaction (tx/begin-tx)]
  (tx/with-transaction
    transaction
    true
    (let [[_ result] (tx/execute transaction [(tx/statement "CREATE (n) RETURN ID(n)")])]
    (println result))))

If there any errors while processing, the transaction is rolled back.

The first argument is the variable which holds the transaction information. The second argument to the macro is commit-on-success, which commits the transaction there are no errors.

Change Log

We encourage all users to give this version (and Neo4J 2.0!) a try.

Neocons change log is available on GitHub.

Neocons is a ClojureWerkz Project

Neocons is part of the group of libraries known as ClojureWerkz, together with

• Langohr, a Clojure client for RabbitMQ that embraces the AMQP 0.9.1 model
• Elastisch, a minimalistic Clojure client for ElasticSearch
• Monger, a Clojure MongoDB client for a more civilized age
• Welle, a Riak client with batteries included
• Quartzite, a powerful scheduling library

and several others. If you like Neocons, you may also like our other projects.

Let us know what you think on Twitter or on the Clojure mailing list.

Michael on behalf of the ClojureWerkz Team